US20160164403A1 - Charge pump circuit - Google Patents
Charge pump circuit Download PDFInfo
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- US20160164403A1 US20160164403A1 US14/956,061 US201514956061A US2016164403A1 US 20160164403 A1 US20160164403 A1 US 20160164403A1 US 201514956061 A US201514956061 A US 201514956061A US 2016164403 A1 US2016164403 A1 US 2016164403A1
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/06—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider
- H02M3/07—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider using capacitors charged and discharged alternately by semiconductor devices with control electrode, e.g. charge pumps
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/06—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider
- H02M3/07—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using resistors or capacitors, e.g. potential divider using capacitors charged and discharged alternately by semiconductor devices with control electrode, e.g. charge pumps
- H02M3/073—Charge pumps of the Schenkel-type
Definitions
- a charge pump circuit is a Direct Current (DC) to DC converter that generates a voltage having a voltage level higher (positive pump) than a voltage level of an input supply voltage or lower (negative pump) than a voltage level of a reference ground voltage.
- a charge pump circuit includes capacitors as energy storage elements and transistors as storage transfer elements.
- the transistors are turned on or off responsive to various control signals, and the control signals are bounded by the voltage levels of the input supply voltage and the reference ground voltage.
- various drain/source terminals of the transistors have up/down shifted voltages by the operations of charging and level-shifting the voltage levels at the capacitors of the charge pump circuit.
- the various up/down shifted voltages have voltage levels beyond the voltage range between the input supply voltage and the reference ground voltage.
- FIG. 1 is a functional block diagram of a charge pump circuit, in accordance with some embodiments.
- FIG. 2 is a circuit schematic diagram of a pumping stage circuit usable in the charge pump circuit in FIG. 1 , in accordance with some embodiments.
- FIG. 3 is a circuit schematic diagram of an output stage circuit usable in the charge pump circuit in FIG. 1 , in accordance with some embodiments.
- FIG. 4 is a circuit schematic diagram of a control circuit usable in the charge pump circuit in FIG. 1 , in accordance with some embodiments.
- FIGS. 5A and 5B are circuit schematic diagrams of two example diode devices usable as the diode devices in the pumping stage circuit in FIG. 2 or in the output stage circuit in FIG. 3 , in accordance with some embodiments.
- FIG. 6 is a timing diagram of voltage levels at various nodes of the charge pump circuit in FIG. 1 , which is further illustrated in conjunction with FIGS. 2-4 , in accordance with some embodiments.
- FIG. 7 is a flow chart of a method of operating a pumping stage circuit in FIG. 2 , in accordance with some embodiments.
- FIG. 8 is a circuit schematic diagram of a signal generation circuit usable in the control circuit of FIG. 4 , in accordance with some embodiments.
- first and second features are formed in direct contact
- additional features may be formed between the first and second features, such that the first and second features may not be in direct contact
- present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
- spatially relative terms such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures.
- the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.
- the apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
- a pumping stage circuit or an output stage circuit of a charge pump circuit includes a transistor, a capacitive device coupled with a gate terminal of the transistor, and two diode devices between the gate terminal and a source/drain (S/D) terminal of the transistor.
- the two diode devices are coupled in an inverse-parallel manner. Through a discharge path provided by one of the two diode devices and the DC separation between the gate terminal of the transistor and a driving signal, the voltage difference between the gate terminal and the S/D terminal is kept at about a forward voltage drop of the one of the two diode devices.
- FIG. 1 is a functional block diagram of a charge pump circuit 100 , in accordance with some embodiments.
- Charge pump circuit 100 includes an input node 102 , an output node 104 , a reference voltage terminal 106 , N pumping stage circuits 110 [ 1 ], 110 [ 2 ], and 110 [N], an output stage circuit 120 , and a control circuit 130 .
- N is a positive integer equal to or greater than one.
- Pumping stage circuits 110 [ 1 ], 110 [ 2 ], and 110 [N] and output stage circuit 120 are coupled between input node 102 and output node 104 .
- Control circuit 130 is coupled with output node 104 and reference voltage terminal 106 , and is configured to generate a plurality of control signals SW[ 1 ], SW[ 2 ], SW[N], SWF, CP[ 1 ], CP[ 2 ], and CP[N] for controlling the operation of pumping stage circuits 110 [ 1 ], 110 [ 2 ], and 110 [N] and output stage circuit 120 .
- Each pumping stage circuit of pumping stage circuits 110 [ 1 ], 110 [ 2 ], and 110 [N] includes an input terminal IN, an output terminal OUT, and control signal terminals SW and CP.
- Output stage circuit 120 includes an input terminal IN, an output terminal OUT, and a control signal terminal SW.
- the input terminal IN of the first pumping stage circuit 110 [ 1 ] is coupled with the input node 102 .
- the output terminal OUT of a n-th pumping stage circuit 110 [ n ] is coupled with the input terminal IN of a (n+1)-th pumping stage circuit 110 [ n+ 1], where n is a positive integer and 1 ⁇ n ⁇ (N ⁇ 1).
- the output terminal OUT of the N-th pumping stage circuit 110 [N] is coupled with the input terminal IN of the output stage circuit 120 .
- the output terminal OUT of the output stage circuit 120 is coupled with the output node 104 .
- pumping stage circuits 110 [ 1 ], 110 [ 2 ], and 110 [N] are configured to convert a voltage at input node 102 having a voltage level V IN to a predetermined voltage level V OUT at output node 104 .
- the voltage level at output terminal OUT of pumping stage circuit 110 [ 1 ] switches between V IN and V 1 ; the voltage level at output terminal OUT of pumping stage circuit 110 [ 2 ] switches between V 1 and V 2 ; the voltage level at input terminal IN of pumping stage circuit 110 [N] switches between V N ⁇ 2 and V N ⁇ 1 ; and the voltage level at output terminal OUT of pumping stage circuit 110 [N] switches between V N ⁇ 1 and V OUT .
- the voltage level at output terminal OUT of pumping stage circuit 110 [ n ] switches between V n ⁇ 1 and V n according to the following equations:
- V 0 V N ;
- V n V N +n *( ⁇ V/N ), n is a positive integer and 1 ⁇ n ⁇ ( N ⁇ 1) (4)
- voltage level V OUT is greater than voltage level V IN , charge pump circuit 100 functions as a positive pump, and ⁇ V thus has a positive value. In some embodiments, voltage level V OUT is less than voltage level V IN , charge pump circuit 100 functions as a negative pump, and ⁇ V thus has a negative value.
- control signal terminal SW of pumping stage circuit 110 [ 1 ] is configured to receive control signal SW[ 1 ]; and control signal terminal CP of pumping stage circuit 110 [ 1 ] is configured to receive control signal CP[ 1 ].
- Control signal terminal SW of pumping stage circuit 110 [ 2 ] is configured to receive control signal SW[ 2 ]; and control signal terminal CP of pumping stage circuit 110 [ 2 ] is configured to receive control signal CP[ 2 ].
- Control signal terminal SW of pumping stage circuit 110 [N] is configured to receive control signal SW[N]; and control signal terminal CP of pumping stage circuit 110 [N] is configured to receive control signal CP[N].
- Control signal terminal SW of output stage circuit 120 is configured to receive control signal SWF.
- Example implementations and operation of pumping stage circuits 110 [ 1 ], 110 [ 2 ], and 110 [N] and output stage circuit 120 in response to various control signals are further described in detail in conjunction with FIGS. 2 and 6 .
- Control circuit 130 is coupled with output node 104 and reference voltage terminal 106 and is configured to generate the plurality of control signals SW[ 1 ], SW[ 2 ], SW[N], SWF, CP[ 1 ], CP[ 2 ], and CP[N] based on the voltage level V OUT at output node 104 and a reference voltage level V REF at reference voltage terminal 106 .
- a signal SW[n] and a corresponding signal CP[n] have the same waveform.
- a signal SW[n] has a pulse width of the voltage level (corresponding to the logic high value) different than that of a corresponding signal CP[n].
- all odd-numbered signals SW[n] have the same first waveform, and all even-numbered signals SW[n] have the same second waveform.
- the first waveform and the second waveform are not at a voltage level corresponding to a logic high value concurrently, and odd-numbered signals SW[n] and even-numbered signals SW[n] are thus referred to as non-overlapping signals.
- all odd-numbered signals CP[n] have the same third waveform, and all even-numbered signals CP[n] have the same fourth waveform.
- the third waveform and the fourth waveform are not concurrently at the voltage level corresponding to a logic high value, and odd-numbered signals CP[n] and even-numbered signals CP[n] are thus referred to as non-overlapping signals.
- control circuit 130 An example implementation and operation of control circuit 130 are further described in detail in conjunction with FIG. 4 .
- FIG. 2 is a circuit schematic diagram of a pumping stage circuit 200 usable in charge pump circuit 100 in FIG. 1 , in accordance with some embodiments.
- pumping stage circuit 200 is usable as any one or all of pumping stage circuits 110 [ 1 ], 110 [ 2 ], and 110 [N].
- Pumping stage circuit 200 includes an input terminal IN, an output terminal OUT, and control signal terminals SW and CP variously corresponding to the terminals IN, OUT, SW, and CP of pumping stage circuits 110 [ 1 ], 110 [ 2 ], or 110 [N] in FIG. 1 .
- input terminal IN has a voltage V S
- output terminal OUT has a voltage V D .
- Control signal terminal SW is configured to receive a control signal S 1 , which corresponds to control signal SW[ 1 ], SW[ 2 ], or SW[N].
- Control signal terminal CP is configured to receive a control signal S 2 , which corresponds to control signal CP[ 1 ], CP[ 2 ], or CP[N].
- Pumping stage circuit 200 includes a transistor 210 , a first capacitive device 222 , a second capacitive device 224 , a first diode device 232 , a second diode device 234 , a first driver 242 , and a second driver 244 .
- Transistor 210 is an N-type transistor and functions as a switching device. In some embodiments, transistor 210 is implemented by a P-type transistor or other suitable switching devices. Transistor 210 includes a gate terminal 212 , a first S/D terminal 214 , and a second S/D terminal 216 . First S/D terminal 214 is coupled with input terminal IN. Second S/D terminal 216 is coupled with output terminal OUT. Gate terminal 212 has a voltage V G .
- First capacitive device 222 has a first end coupled with the gate terminal 212 of transistor 210 and a second end configured to receive a driving signal S 3 .
- Second capacitive device 224 has a first end coupled with the output terminal OUT and a second end configured to receive a driving signal S 4 .
- First diode device 232 has a cathode coupled with second S/D terminal 216 of transistor 210 and an anode coupled with gate terminal 212 of transistor 210 .
- Second diode device 234 has a cathode coupled with gate terminal 212 of transistor 210 and an anode coupled with second S/D terminal 216 of transistor 210 .
- First driver 242 is configured to generate the driving signal S 3 based on the control signal S 1 .
- Second driver 244 is configured to generate the driving signal S 4 based on the control signal S 2 .
- First driver 242 is an inverter having an input terminal coupled with control signal terminal SW and an output terminal coupled with the second end of capacitive device 222 .
- Second driver 244 is an inverter having an input terminal coupled with control signal terminal CP and an output terminal coupled with the second end of capacitive device 224 .
- first driver 242 and second driver 244 are implemented by one or a combination of an inverter, a buffer, a level shifter, or other suitable devices.
- each signal of signal S 1 , S 2 , S 3 , and S 4 switches between a first voltage level corresponding to a logic high value (hereinafter the “first logic high level”) and a reference ground voltage level corresponding to a logic low value (hereinafter the “logic low level”).
- first logic high level a logic high value
- logic low level a reference ground voltage level corresponding to a logic low value
- each signal of signals S 3 and S 4 switches between the first logic high level and the logic low level
- each signal of signals S 1 and S 2 switches between a second voltage level corresponding to the logic high value (hereinafter the “second logic high level”) and the logic low level.
- the second logic high level is greater than the first logic high level.
- a diode device has a forward voltage drop between an anode and a cathode thereof when the diode device is forward biased and conductive.
- first diode device 232 has a forward voltage drop V FB1
- second diode device 234 has a forward voltage drop V FB2
- forward voltage drop V FB1 is greater than forward voltage drop V FB2 .
- transistor 210 has a threshold voltage V TH between gate terminal 212 and S/D terminal 216 . In some embodiments, forward voltage drop V FB1 is greater than threshold voltage V TH of transistor 210 .
- diode device 232 is configured to provide a discharge path between gate terminal 212 and S/D terminal 216 in order to reduce a voltage difference between voltage V G and voltage V D to be no greater than forward voltage drop V FB1 of diode device 232 when diode device 232 is forward biased and conductive.
- diode device 234 is configured to provide a discharge path between gate terminal 212 and S/D terminal 216 in order to limit a voltage difference between voltage V G and voltage V D to be no greater than forward voltage drop V FB2 of diode device 234 when diode device 234 is forward biased and conductive.
- diode devices 232 and 234 also provide conductive paths to reduce the peak voltage levels of voltage V G and voltage V D when these voltages are being switched in response to the transitions of signals S 3 and S 4 and by the operation of capacitive devices 222 and 224 .
- diode devices 232 and 234 thereby act to guarantee that the DC value on capacitor 222 is always in the correct range in order to turn on and off transistor 210 .
- diode device 232 includes a series of one or more diodes and forward voltage drop V FB1 of diode device 232 is the sum of the voltage drops of each diode of the diode series.
- diode device 234 includes a series of one or more diodes and forward voltage drop V FB2 of diode device 234 is the sum of the voltage drops of each diode of the diode series.
- capacitive device 222 level-shifts driving signal S 3 such that the need to generate control signals having a large voltage swing is avoided. This feature simplifies circuit design and makes it possible to implement a charge pump without the costs associated with a high voltage capability. Detailed operation of various components of pumping stage circuit 200 is illustrated in conjunction with FIG. 6 .
- FIG. 3 is a circuit schematic diagram of an output stage circuit 300 usable in charge pump circuit 100 in FIG. 1 , in accordance with some embodiments. Components in FIG. 3 that are the same or similar to those in FIG. 2 are given the same reference labels, and detailed description thereof is thus omitted.
- output stage circuit 300 does not have control signal terminal CP and driver 244 .
- Capacitive device 224 is coupled between output terminal and a supply reference terminal 310 .
- supply reference terminal 310 has a voltage level corresponding to a reference ground voltage level or the zero volt level. In some embodiments, supply reference terminal 310 has a voltage level the same as the logic low level.
- output stage circuit 300 stores and holds at capacitive device 224 the charges from a previous pumping stage circuit and outputs a voltage at output terminal OUT having a predetermined pumped voltage level.
- the capacitance value of the capacitive device 224 in the output stage circuit 300 is set to be sufficiently large to substantially hold the predetermined pumped voltage level while allowing a predetermined current to be drawn by an external circuit.
- FIG. 4 is a circuit schematic diagram of a control circuit 400 usable in charge pump circuit 100 in FIG. 1 , in accordance with some embodiments.
- Control circuit 400 includes a feedback voltage terminal 402 , a reference voltage terminal 404 , a supply voltage terminal 408 , resistive devices 412 and 414 , a comparator 420 , a signal generation circuit 430 , and a plurality of control lines 440 .
- control circuit 400 includes a clock terminal 406 .
- Feedback voltage terminal 402 is coupled with output node 104 of charge pump circuit 100 .
- Reference voltage terminal 404 is configured to receive a reference voltage having the reference voltage level V REF .
- Supply voltage terminal 408 is configured to carry a voltage having a supply voltage level. In some embodiments, the supply voltage level is the same as the first logic high level or the second logic high level.
- Resistive devices 412 and 414 are coupled in series between supply voltage terminal 408 and feedback voltage terminal 402 . Resistive devices 412 and 414 are configured as a voltage divider to convert the voltage at output node 104 to a feedback voltage having a voltage level V FB comparable to the reference voltage level V REF .
- Comparator 420 includes a first input terminal 422 , a second input terminal 424 , and an output terminal 426 .
- First input terminal 422 is configured to receive the reference voltage (having the reference voltage level V REF ).
- Second input terminal 424 is configured to receive the feedback voltage (having the feedback voltage level V FB ).
- Comparator 420 compares the values of reference voltage level V REF and feedback voltage level V FB and generates a comparison result at output terminal 426 .
- Signal generation circuit 430 is coupled with the output terminal 426 of comparator 420 and, if present, clock terminal 406 .
- Signal generation circuit 430 is also coupled with pumping stage circuits 110 [ 1 ], 110 [ 2 ], and 110 [N] and output stage circuit 120 through the plurality of control lines 440 .
- Signal generation circuit 430 is configured to receive the comparison result at output terminal 426 of comparator 420 and a clock signal CLK from clock terminal 406 , and generate control signals SW[ 1 ], SW[ 2 ], SW[N], SWF, CP[ 1 ], CP[ 2 ], and CP[N] on the plurality of control lines 440 .
- signal generation circuit 430 is further configured to receive a clock signal CLK from clock terminal 406 .
- Control circuit 400 is a non-limiting example.
- Other types of control circuits usable to generate control signals SW[ 1 ], SW[ 2 ], SW[N], SWF, CP[ 1 ], CP[ 2 ], and CP[N] to control charge pump circuit 100 based on the pulse width, frequencies, or amplitude information thereof are within the scope of various embodiments of the present disclosure.
- FIG. 8 is a circuit schematic diagram of an example signal generation circuit 800 usable as a signal generation circuit 430 in the control circuit in FIG. 4 , in accordance with some embodiments.
- Signal generation circuit 800 includes a D-flip-flop (DFF) 802 , an AND gate 804 , and a two-phase, non-overlapping clock generator 808 .
- DFF 802 includes a clock input terminal 806 and a comparator input terminal 826 .
- Two-phase, non-overlapping clock generator 808 includes a first output terminal 810 and a second output terminal 812 .
- DFF 802 is configured to receive clock signal CLK at clock input terminal 806 and to receive a comparator output, e.g. the comparison result at output terminal 426 , at logic input terminal 826 . DFF 802 samples the comparator output based on clock signal CLK and outputs a sampled comparator output.
- AND gate 804 is configured to receive the sampled comparator output from DFF 802 and clock signal CLK, and provide a gated output to two-phase, non-overlapping clock generator 808 . In response to a logic high level of the sampled comparator output, AND gate 804 is configured to output a gated clock signal. In response to a logic low level of the sampled comparator output, AND gate 804 is configured to output a logic low level.
- Two-phase, non-overlapping clock generator 808 is configured to receive the gated clock signal from AND gate 804 , and in response, create a first pulse signal A at first output terminal 810 and a second pulse signal B at second output terminal 812 .
- first pulse signal A and second pulse signal B are used as charge pump control signals SW[i] and CP[i].
- first output terminal 810 and second output terminal 812 are coupled with the plurality of control lines 440 .
- first pulse signal A is used as charge pump control signal SW[i] for even values of i and second pulse signal B is used as charge pump control signal SW[i] for odd values of i.
- first pulse signal A is used as charge pump control signal CP[i] for odd values of i and second pulse signal B is used as charge pump control signal CP[i] for even values of i.
- signal generation circuit 800 responds to the comparator output by generating first pulse signal A and second pulse signal B when feedback voltage level V FB is above reference voltage level V REF , and by not generating first pulse signal A and second pulse signal B when feedback voltage level V FB is below reference voltage level V REF .
- Signal generation circuit 800 is a non-limiting example.
- Other types of signal generation circuits usable to generate control signals SW[ 1 ], SW[ 2 ], SW[N], SWF, CP[ 1 ], CP[ 2 ], and CP[N] to control charge pump circuit 100 are within the scope of various embodiments of the present disclosure.
- FIG. 5A is a circuit schematic diagram of an example diode device 500 A usable as a diode device 232 or 234 in pumping stage circuit 200 in FIG. 2 or in output stage circuit 300 in FIG. 3 , in accordance with some embodiments.
- Diode device 500 A includes an anode terminal 502 , a cathode terminal 504 , and J diode-connected P-type transistors 510 [ 1 ] to 510 [J] between anode terminal 502 and cathode terminal 504 .
- J is a positive integer greater than zero.
- P-type transistors 510 [ 1 ] to 510 [J] are coupled in series when J is greater than one.
- diode device 242 has a forward voltage drop V FB1 greater than a forward voltage drop V FB2 of diode device 244 . Therefore, Y is set to be less than X.
- FIG. 5B is a circuit schematic diagram of another example diode device 500 B usable as a diode device 232 or 234 in pumping stage circuit 200 in FIG. 2 or in output stage circuit 300 in FIG. 3 , in accordance with some embodiments.
- Components in FIG. 5B that are the same or similar to those in FIG. 5A are given the same reference labels, and detailed description thereof is thus omitted.
- Diode device 500 B includes K diode-connected N-type transistors 520 [ 1 ] to 520 [K] between anode terminal 502 and cathode terminal 504 .
- K is a positive integer greater than zero.
- N-type transistors 520 [ 1 ] to 520 [K] are coupled in series when K is greater than one.
- diode device 232 has a forward voltage drop V FB1 greater than a forward voltage drop V FB2 of diode device 234 . Therefore, Y is set to be less than X.
- one of diode device 232 or diode device 234 is implemented based on the configuration of diode device 500 A, and the other one of diode device 232 or diode device 234 is implemented based on the configuration of diode device 500 B. In some embodiments, diode device 232 or diode device 234 is implemented by other types of diode devices different from diode device 500 A and diode device 500 B.
- FIG. 6 is a timing diagram of voltage levels at various nodes of charge pump circuit 100 in FIG. 1 , which is further illustrated in conjunction with FIGS. 2-4 , in accordance with some embodiments.
- the number of pumping stage circuits (i.e., the number N in FIG. 1 ) is set to be two, and charge pump circuit is configured to be a negative pump.
- the voltage level V IN is set to be 0 V
- the voltage level V OUT is set to be ⁇ 2.2 V.
- the charge pump circuit as illustrated in conjunction with FIGS. 1-4 is also usable as a positive pump. Different configurations and settings of the charge pump circuit 100 are within various embodiments of the present disclosure.
- Waveform 602 corresponds to the voltage level of signal S 1 of first pumping stage circuit 110 [ 1 ].
- Waveform 604 corresponds to the voltage level of signal S 2 of first pumping stage circuit 110 [ 1 ].
- Waveform 612 corresponds to the voltage level of voltage V D of first pumping stage circuit 110 [ 1 ].
- Waveform 614 corresponds to the voltage level of voltage V G of first pumping stage circuit 110 [ 1 ].
- Waveform 622 corresponds to the voltage level of voltage V D of second pumping stage circuit 110 [ 2 ].
- Waveform 632 corresponds to the voltage level of voltage V D of output stage circuit 120 .
- the following illustration, if not otherwise specified, is primarily based on the operation of first pumping stage circuit 110 [ 1 ] using the reference labels from pumping stage circuit 200 in FIG. 2 .
- the operations of transistors 210 and capacitive device 222 of second pumping stage circuit 110 [ 2 ] and output stage circuit 120 are similar to the operations of transistor 210 and capacitive device 222 of first pumping stage circuit 110 [ 1 ].
- the operation of capacitive device 224 of second pumping stage circuit 110 [ 2 ] is similar to the operation of capacitive device 224 of first pumping stage circuit 110 [ 1 ]. Detailed description thereof is thus omitted.
- each signal of signals S 1 , S 2 , S 3 , and S 4 has a logic high level of 1.8 volts (V) and a logic low level of 0.0 V. In some embodiments, each signal of signals S 1 and S 3 has a logic high level different from that of signal S 2 and S 4 . In some embodiments, each signal of signals S 1 and S 3 has a logic high level of 2.5 V, and each signal of signals S 2 and S 4 has a logic high level of 1.8 V.
- signal S 1 (waveform 602 ) and signal S 2 (waveform 604 ) of first pumping stage circuit 110 [ 1 ] are at the low logic level.
- Signal S 3 (not shown) and signal S 4 (not shown) of first pumping stage circuit 110 [ 1 ] are thus at the signal high level.
- Voltage V D of first pumping stage circuit 110 [ 1 ] is at an input voltage level from a power source or a previous pumping stage circuit, such as 0.0 volt for first pumping stage circuit 110 [ 1 ] in this example.
- voltage V G of first pumping stage circuit 110 [ 1 ] is at a voltage level that equals the input voltage level plus the forward voltage drop V FB1 of diode device 232 , such as V FB1 in this example. Because forward voltage drop V FB1 is set to be greater than threshold voltage V TH of transistor 210 , transistor 210 is turned on to pass the input voltage level (e.g., 0.0 V in this example) to voltage V D .
- signal S 1 transitions from the low logic level to the high logic level.
- Signal S 2 (waveform 604 ) remains at the low logic level.
- Signal S 3 (not shown) thus transitions from the high logic level to the low logic level while signal S 4 (not shown) remains at the signal high level.
- voltage V G waveform 614 of first pumping stage circuit 110 [ 1 ] is pushed down by about 1.8 V.
- diode device 234 of first pumping stage circuit 110 [ 1 ] is also providing a discharge path to pull voltage V G (waveform 614 ) and voltage V D (waveform 612 ) toward each other.
- voltage V G transitions from voltage level V FB1 to a voltage level that is a few hundred millivolts (mV) higher than a voltage level of voltage level V FB1 minus 1.8 V.
- the voltage differences between the gate terminal of transistor 210 and S/D terminals of transistor 210 are insufficient to turn on transistor 210 .
- Voltage V D (waveform 614 ) remains at 0.0 V. Transistor 210 is thus turned off.
- time period between time T 1 and time T 2 is set to be insufficient to pull voltage V G to be sufficiently large to turn on transistor 210 at time T 2 .
- the time period between time T 1 and time T 2 is sufficiently small that the voltage change of voltage V G (waveform 614 ) or the voltage change of voltage V D (waveform 612 ) is less than 100 mV.
- signal S 2 transitions from the low logic level to the high logic level.
- Signal S 1 (waveform 602 ) remains at the high logic level.
- Signal S 4 (not shown) thus transitions from the high logic level to the low logic level while signal S 3 (not shown) remains at the signal low level.
- voltage V D (waveform 612 ) is being pushed down by about 1.8 V.
- voltage V D is also being pulled toward a steady state output voltage level of this pumping stage, such as ⁇ 1.1 V in this example.
- the charge sharing is also controlled by adjusting the frequencies of control signals SW[ 1 ], SW[ 2 ], SW[N], SWF, CP[ 1 ], CP[ 2 ], and CP[N] and/or by adjusting the voltage level of signal S 4 .
- Voltage V G (waveform 314 ) is pulled down slightly at time T 2 when diode device 234 goes from conductive to reverse-biased. As a result, at time T 2 , voltage V D (waveform 612 ) transitions from 0.0 V to a voltage level that is a few hundred mV higher than a voltage level of ⁇ 1.8 V. Transistor 210 remains turned off.
- voltage V G (waveform 614 ) remains at about the same voltage level after diode devices 232 and 234 reach their charge balance states after being turned off.
- Voltage V D (waveform 612 ) is pulled toward and then remains at the steady state output voltage level (e.g., ⁇ 1.1 V in this example). In this example, the voltage level of V G is greater than the voltage level of V D , but the voltage difference therebetween is insufficient to turn on transistor 210 . Transistor 210 remains turned off.
- signal S 2 transitions from the high logic level to the low logic level.
- Signal S 1 (waveform 602 ) remains at the high logic level.
- Signal S 4 (not shown) thus transitions from the low logic level to the high logic level while signal S 3 (not shown) remains at the signal low level.
- voltage V D (waveform 612 ) is being pulled up by about 1.8 V.
- diode device 234 is also providing a discharge path to pull voltage V G (waveform 614 ) and voltage V D (waveform 612 ) toward each other.
- voltage V D transitions from the steady state output voltage level (e.g., ⁇ 1.1 V in this example) to a voltage level that is a few hundred mV lower than a voltage level of 0.7 V (i.e, ⁇ 1.1 V plus 1.8 V).
- the voltage differences between the gate terminal of transistor 210 and S/D terminals of transistor 210 are insufficient to turn on transistor 210 .
- Transistor 210 remains turned off.
- time T 3 After time T 3 but before time T 4 , voltage V G (waveform 614 ) and voltage V D (waveform 612 ) are pulled toward each other through diode device 234 .
- Transistor 210 remains turned off.
- the time period between time T 3 and time T 4 is sufficiently small that the voltage change of voltage V G (waveform 314 ) or the voltage change of voltage V D (waveform 612 ) is less than 100 mV.
- signal S 1 transitions from the high logic level to the low logic level.
- Signal S 2 transition 604 ) remains at the low logic level.
- Signal S 3 thus transitions from the low logic level to the high logic level while signal S 4 (not shown) remains at the signal high level.
- voltage V G waveform 614
- diode device 232 is also providing a discharge path to pull voltage V G (waveform 614 ) toward voltage V D .
- voltage V G transitions to a voltage level that is a few hundred mV higher than voltage level V FB1 .
- the voltage difference between the gate terminal of transistor 210 and S/D terminal 216 is sufficient to turn on transistor 210 .
- voltage V D (waveform 612 ) is pulled toward and then remains at the steady state input voltage level (e.g., 0 V in this example), and voltage V G (waveform 614 ) is pulled toward and then remains at about forward voltage drop V FB1 of diode device 232 plus the steady state input voltage level.
- Transistor 210 remains turned on.
- Time T 5 corresponds to time T 1 of the next operation cycle.
- Second pumping stage circuit 110 [ 2 ] is operated in a manner similar to first pumping stage circuit 110 [ 1 ], except the corresponding control signals thereof are non-overlapping signals to the counterpart signals of first pumping stage circuit 110 [ 1 ].
- voltage V D of pumping stage circuit 110 [ 2 ] (waveform 622 ) is at ⁇ 1.1V during time T 1 to time T 4 and is pumped to ⁇ 2.2 V during time T 4 to time T 5 .
- Transistor 210 of output stage circuit 120 is operated in a manner similar to transistor 210 of first input stage 110 [ 1 ].
- Capacitive device 224 of output stage circuit 120 is configured to hold the voltage level of voltage V D at ⁇ 2.2 V when transistor 210 of output stage circuit 120 is turned off during time T 1 to time T 4 .
- Capacitive device 224 of output stage circuit 120 is also configured to receive the charges from the capacitive device 224 of second pumping stage circuit 110 [ 2 ] when transistor 210 of output stage circuit 120 is turned on during time T 4 to time T 5 . As a result, voltage V D of output stage circuit 120 remains at ⁇ 2.2 V.
- forward voltage drop V FB1 of diode device 232 is set to be less than the logic high level, such as 1.8 V in this example.
- a transistor corresponding to transistor 210 thus has a gate terminal to S/D terminal voltage adjusted by forward voltage drop V FB1 of diode device 232 , which is less than the logic high level when the transistor 210 is turned on.
- FIG. 7 is a flow chart of a method 700 of operating a pumping stage circuit in FIG. 2 , in accordance with some embodiments.
- FIG. 7 is illustrated in conjunction with the example depicted in FIG. 2 . It is understood that additional operations may be performed before, during, and/or after the method 700 depicted in FIG. 7 , and that some other processes may only be briefly described herein.
- Method 700 begins with operation 710 , where a voltage level at a first end of a capacitive device, such as signal S 3 between driver 242 and capacitive device 222 , is caused to transition from a first voltage level to a second voltage level responsive to a first logic value of a control signal.
- the first voltage level corresponds to a logic low level
- the second voltage level corresponds to a logic high level
- the control signal corresponds to signal S 1
- the first logic value corresponds to a logic low value.
- Method 700 proceeds to operation 720 , where a voltage level at a second end of capacitive device 222 , such as voltage V G , is caused to transition to a third voltage level responsive to the second voltage level at the first end of the capacitive device.
- the second end of capacitive device 222 is electrically coupled with a gate terminal 212 of a transistor 210 .
- operations 710 and 720 correspond to the signal transitions at time T 4 in the timing diagram in FIG. 6 .
- Method 700 proceeds to operation 730 , where a first voltage difference between gate terminal 212 and a source/drain (S/D) terminal 216 of transistor 210 is adjusted by a first diode device, such as diode device 232 , when transistor 210 is turned on and first diode device 232 is forward biased and conductive.
- First diode device 232 has an anode coupled with gate terminal 212 of transistor 210 and a cathode coupled with S/D terminal 216 of transistor 210 .
- operation 730 corresponds to the signal transitions from time T 4 to time T 5 in the timing diagram in FIG. 6 .
- Method 700 proceeds to operation 740 , where a voltage level (e.g., signal S 3 ) at the first end of capacitive device 222 is caused to transition from the second voltage level to the first voltage level responsive to a second logic value of a control signal.
- the second logic value corresponds to a logic high value.
- voltage V G is caused to transition to a fourth voltage level that is insufficient to turn on transistor 210 .
- operation 740 corresponds to the signal transitions at time T 1 in the timing diagram in FIG. 6 .
- Method 700 proceeds to operation 750 , where a second voltage difference between S/D terminal 216 of the transistor 210 and gate terminal 212 of transistor 201 is adjusted by a second diode device, such as diode device 234 , when the transistor 210 is turned on and the second diode device 234 is forward biased and conductive.
- Second diode device 234 has an anode coupled with the S/D terminal 216 of the transistor 210 and a cathode coupled with the gate terminal 212 of the transistor 210 .
- operation 750 corresponds to the signal transitions from time T 1 to time T 2 and/or from time T 3 to time T 4 in the timing diagram in FIG. 6 .
- first diode device 232 has a forward voltage drop V FB1
- second diode device 234 has a forward voltage drop V FB2
- forward voltage drop V FB1 is greater than forward voltage drop V FB2
- transistor 210 has a threshold voltage V TH between gate terminal 212 and S/D terminal 216 .
- forward voltage drop V FB1 is greater than threshold voltage V TH of transistor 210 .
- operations 710 - 750 are applicable to a method of operating an output stage circuit 300 in FIG. 3 .
- Method 700 proceeds to operation 760 , where a voltage level at S/D terminal 216 of transistor 210 is pumped to a predetermined pumped voltage level in response to another control signal, such as control signal S 2 .
- operation 760 corresponds to the signal transitions from time T 2 to time T 3 in the timing diagram in FIG. 6 .
- a charge pump circuit includes a sub-circuit, which is a pumping stage circuit or an output stage circuit.
- the sub-circuit includes an input terminal, an output terminal, a transistor, a first capacitive device, a first diode device, and a second diode device.
- the transistor has a first source/drain (S/D) terminal coupled with the input terminal, a second S/D terminal coupled with the output terminal, and a gate terminal.
- the first capacitive device has a first end coupled with the gate terminal of the transistor and a second end configured to receive a first driving signal.
- the first diode device has a cathode coupled with the second S/D terminal of the transistor and an anode coupled with the gate terminal of the transistor.
- the second diode device has a cathode coupled with the gate terminal of the transistor and an anode coupled with the second S/D terminal of the transistor.
- a charge pump circuit includes an input node, an output node, N pumping stage circuits, and an output stage circuit.
- N is a positive integer greater than zero.
- Each pumping stage circuit of the N pumping stage circuits includes an input terminal and an output terminal.
- the output stage circuit includes an input terminal and an output terminal.
- the input terminal of a first pumping stage circuit of the N pumping stage circuits is coupled with the input node.
- the output terminal of a n-th pumping stage circuit of the N pumping stage circuits is coupled with the input terminal of a (n+1)-th pumping stage circuit of the N pumping stage circuits, where n is a positive integer and 1 ⁇ n ⁇ (N ⁇ 1).
- the output terminal of the N-th pumping stage circuit of the N pumping stage circuits is coupled with the input terminal of the output stage circuit.
- the output terminal of the output stage circuit is coupled with the output node.
- One of the N pumping stage circuits further includes a transistor, a first capacitive device, a second capacitive device, a first diode device, and a second diode device.
- the transistor has a first source/drain (S/D) terminal coupled with the input node of the one of the N pumping stage circuits, a second S/D terminal coupled with the output node of the one of the N pumping stage circuits, and a gate terminal.
- the first capacitive device has a first end coupled with the gate terminal of the transistor and a second end configured to receive a first driving signal.
- the second capacitive device has a first end coupled with the output node of the one of the N pumping stage circuits and a second end configured to receive a second driving signal.
- the first diode device has a cathode coupled with the second S/D terminal of the transistor and an anode coupled with the gate terminal of the transistor.
- the second diode device has a cathode coupled with the gate terminal of the transistor and an anode coupled with the second S/D terminal of the transistor.
- a method of operating a pumping stage circuit or an output stage circuit of a charge pump circuit includes causing a voltage level at a first end of a capacitive device to transition from a first voltage level to a second voltage level responsive to a first logic value of a control signal.
- the method also includes causing a voltage level at a second end of the capacitive device to transition to a third voltage level responsive to the second voltage level at the first end of the capacitive device, the second end of the capacitive device being electrically coupled with a gate terminal of a transistor; and adjusting a first voltage difference between the gate terminal and a source/drain (S/D) terminal of the transistor by a first diode device when the transistor is turned on and the first diode device is forward biased and conductive.
- the first diode device has an anode coupled with the gate terminal of the transistor and a cathode coupled with the S/D terminal of the transistor.
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Abstract
Description
- A charge pump circuit is a Direct Current (DC) to DC converter that generates a voltage having a voltage level higher (positive pump) than a voltage level of an input supply voltage or lower (negative pump) than a voltage level of a reference ground voltage. In some applications, a charge pump circuit includes capacitors as energy storage elements and transistors as storage transfer elements. In some applications, the transistors are turned on or off responsive to various control signals, and the control signals are bounded by the voltage levels of the input supply voltage and the reference ground voltage. Also, various drain/source terminals of the transistors have up/down shifted voltages by the operations of charging and level-shifting the voltage levels at the capacitors of the charge pump circuit. In some applications, the various up/down shifted voltages have voltage levels beyond the voltage range between the input supply voltage and the reference ground voltage.
- Aspects of the present disclosure are best understood from the following detailed description when read with the accompanying figures. It is noted that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
-
FIG. 1 is a functional block diagram of a charge pump circuit, in accordance with some embodiments. -
FIG. 2 is a circuit schematic diagram of a pumping stage circuit usable in the charge pump circuit inFIG. 1 , in accordance with some embodiments. -
FIG. 3 is a circuit schematic diagram of an output stage circuit usable in the charge pump circuit inFIG. 1 , in accordance with some embodiments. -
FIG. 4 is a circuit schematic diagram of a control circuit usable in the charge pump circuit inFIG. 1 , in accordance with some embodiments. -
FIGS. 5A and 5B are circuit schematic diagrams of two example diode devices usable as the diode devices in the pumping stage circuit inFIG. 2 or in the output stage circuit inFIG. 3 , in accordance with some embodiments. -
FIG. 6 is a timing diagram of voltage levels at various nodes of the charge pump circuit inFIG. 1 , which is further illustrated in conjunction withFIGS. 2-4 , in accordance with some embodiments. -
FIG. 7 is a flow chart of a method of operating a pumping stage circuit inFIG. 2 , in accordance with some embodiments. -
FIG. 8 is a circuit schematic diagram of a signal generation circuit usable in the control circuit ofFIG. 4 , in accordance with some embodiments. - The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. For example, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed between the first and second features, such that the first and second features may not be in direct contact. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed.
- Further, spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The apparatus may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein may likewise be interpreted accordingly.
- In accordance with some embodiments, a pumping stage circuit or an output stage circuit of a charge pump circuit includes a transistor, a capacitive device coupled with a gate terminal of the transistor, and two diode devices between the gate terminal and a source/drain (S/D) terminal of the transistor. The two diode devices are coupled in an inverse-parallel manner. Through a discharge path provided by one of the two diode devices and the DC separation between the gate terminal of the transistor and a driving signal, the voltage difference between the gate terminal and the S/D terminal is kept at about a forward voltage drop of the one of the two diode devices.
-
FIG. 1 is a functional block diagram of acharge pump circuit 100, in accordance with some embodiments.Charge pump circuit 100 includes aninput node 102, anoutput node 104, areference voltage terminal 106, N pumping stage circuits 110[1], 110[2], and 110[N], anoutput stage circuit 120, and acontrol circuit 130. N is a positive integer equal to or greater than one. Three pumping stage circuits 110[1], 110[2], and 110[N] (i.e., N=3) are depicted inFIG. 1 as a non-limiting example. Pumping stage circuits 110[1], 110[2], and 110[N] andoutput stage circuit 120 are coupled betweeninput node 102 andoutput node 104.Control circuit 130 is coupled withoutput node 104 andreference voltage terminal 106, and is configured to generate a plurality of control signals SW[1], SW[2], SW[N], SWF, CP[1], CP[2], and CP[N] for controlling the operation of pumping stage circuits 110[1], 110[2], and 110[N] andoutput stage circuit 120. - Each pumping stage circuit of pumping stage circuits 110[1], 110[2], and 110[N] includes an input terminal IN, an output terminal OUT, and control signal terminals SW and CP.
Output stage circuit 120 includes an input terminal IN, an output terminal OUT, and a control signal terminal SW. The input terminal IN of the first pumping stage circuit 110[1] is coupled with theinput node 102. The output terminal OUT of a n-th pumping stage circuit 110[n] is coupled with the input terminal IN of a (n+1)-th pumping stage circuit 110[n+1], where n is a positive integer and 1≦n≦(N−1). The output terminal OUT of the N-th pumping stage circuit 110[N] is coupled with the input terminal IN of theoutput stage circuit 120. The output terminal OUT of theoutput stage circuit 120 is coupled with theoutput node 104. - In some embodiments, pumping stage circuits 110[1], 110[2], and 110[N] are configured to convert a voltage at
input node 102 having a voltage level VIN to a predetermined voltage level VOUT atoutput node 104. During a steady state operation ofcharge pump circuit 100 and with transient overshoots or undershoots ignored, the voltage level at output terminal OUT of pumping stage circuit 110[1] switches between VIN and V1; the voltage level at output terminal OUT of pumping stage circuit 110[2] switches between V1 and V2; the voltage level at input terminal IN of pumping stage circuit 110[N] switches between VN−2 and VN−1; and the voltage level at output terminal OUT of pumping stage circuit 110[N] switches between VN−1 and VOUT. In some embodiments, the voltage level at output terminal OUT of pumping stage circuit 110[n] switches between Vn−1 and Vn according to the following equations: -
ΔV=V OUT −V N; (1) -
V0=VN; (2) -
VN=VOUT; and (3) -
V n =V N +n*(ΔV/N), n is a positive integer and 1≦n≦(N−1) (4) - In some embodiments, voltage level VOUT is greater than voltage level VIN,
charge pump circuit 100 functions as a positive pump, and ΔV thus has a positive value. In some embodiments, voltage level VOUT is less than voltage level VIN,charge pump circuit 100 functions as a negative pump, and ΔV thus has a negative value. - Furthermore, control signal terminal SW of pumping stage circuit 110[1] is configured to receive control signal SW[1]; and control signal terminal CP of pumping stage circuit 110[1] is configured to receive control signal CP[1]. Control signal terminal SW of pumping stage circuit 110[2] is configured to receive control signal SW[2]; and control signal terminal CP of pumping stage circuit 110[2] is configured to receive control signal CP[2]. Control signal terminal SW of pumping stage circuit 110[N] is configured to receive control signal SW[N]; and control signal terminal CP of pumping stage circuit 110[N] is configured to receive control signal CP[N]. Control signal terminal SW of
output stage circuit 120 is configured to receive control signal SWF. Example implementations and operation of pumping stage circuits 110[1], 110[2], and 110[N] andoutput stage circuit 120 in response to various control signals are further described in detail in conjunction withFIGS. 2 and 6 . -
Control circuit 130 is coupled withoutput node 104 andreference voltage terminal 106 and is configured to generate the plurality of control signals SW[1], SW[2], SW[N], SWF, CP[1], CP[2], and CP[N] based on the voltage level VOUT atoutput node 104 and a reference voltage level VREF atreference voltage terminal 106. In some embodiments, a signal SW[n] and a corresponding signal CP[n] have the same waveform. In some embodiments, a signal SW[n] has a pulse width of the voltage level (corresponding to the logic high value) different than that of a corresponding signal CP[n]. - In some embodiments, all odd-numbered signals SW[n] have the same first waveform, and all even-numbered signals SW[n] have the same second waveform. In some embodiments, the first waveform and the second waveform are not at a voltage level corresponding to a logic high value concurrently, and odd-numbered signals SW[n] and even-numbered signals SW[n] are thus referred to as non-overlapping signals. In some embodiments, all odd-numbered signals CP[n] have the same third waveform, and all even-numbered signals CP[n] have the same fourth waveform. In some embodiments, the third waveform and the fourth waveform are not concurrently at the voltage level corresponding to a logic high value, and odd-numbered signals CP[n] and even-numbered signals CP[n] are thus referred to as non-overlapping signals.
- An example implementation and operation of
control circuit 130 are further described in detail in conjunction withFIG. 4 . -
FIG. 2 is a circuit schematic diagram of apumping stage circuit 200 usable incharge pump circuit 100 inFIG. 1 , in accordance with some embodiments. In some embodiments, pumpingstage circuit 200 is usable as any one or all of pumping stage circuits 110[1], 110[2], and 110[N]. - Pumping
stage circuit 200 includes an input terminal IN, an output terminal OUT, and control signal terminals SW and CP variously corresponding to the terminals IN, OUT, SW, and CP of pumping stage circuits 110[1], 110[2], or 110[N] inFIG. 1 . For illustration, input terminal IN has a voltage VS, and output terminal OUT has a voltage VD. Control signal terminal SW is configured to receive a control signal S1, which corresponds to control signal SW[1], SW[2], or SW[N]. Control signal terminal CP is configured to receive a control signal S2, which corresponds to control signal CP[1], CP[2], or CP[N]. - Pumping
stage circuit 200 includes atransistor 210, afirst capacitive device 222, asecond capacitive device 224, afirst diode device 232, asecond diode device 234, afirst driver 242, and asecond driver 244. -
Transistor 210 is an N-type transistor and functions as a switching device. In some embodiments,transistor 210 is implemented by a P-type transistor or other suitable switching devices.Transistor 210 includes agate terminal 212, a first S/D terminal 214, and a second S/D terminal 216. First S/D terminal 214 is coupled with input terminal IN. Second S/D terminal 216 is coupled with output terminal OUT.Gate terminal 212 has a voltage VG. - First
capacitive device 222 has a first end coupled with thegate terminal 212 oftransistor 210 and a second end configured to receive a driving signal S3.Second capacitive device 224 has a first end coupled with the output terminal OUT and a second end configured to receive a driving signal S4.First diode device 232 has a cathode coupled with second S/D terminal 216 oftransistor 210 and an anode coupled withgate terminal 212 oftransistor 210.Second diode device 234 has a cathode coupled withgate terminal 212 oftransistor 210 and an anode coupled with second S/D terminal 216 oftransistor 210. -
First driver 242 is configured to generate the driving signal S3 based on the control signal S1. Second driver 244 is configured to generate the driving signal S4 based on the control signal S2. First driver 242 is an inverter having an input terminal coupled with control signal terminal SW and an output terminal coupled with the second end ofcapacitive device 222.Second driver 244 is an inverter having an input terminal coupled with control signal terminal CP and an output terminal coupled with the second end ofcapacitive device 224. In some embodiments,first driver 242 andsecond driver 244 are implemented by one or a combination of an inverter, a buffer, a level shifter, or other suitable devices. In some embodiments, each signal of signal S1, S2, S3, and S4 switches between a first voltage level corresponding to a logic high value (hereinafter the “first logic high level”) and a reference ground voltage level corresponding to a logic low value (hereinafter the “logic low level”). In some embodiments, each signal of signals S3 and S4 switches between the first logic high level and the logic low level, and each signal of signals S1 and S2 switches between a second voltage level corresponding to the logic high value (hereinafter the “second logic high level”) and the logic low level. In some embodiments, the second logic high level is greater than the first logic high level. - A diode device has a forward voltage drop between an anode and a cathode thereof when the diode device is forward biased and conductive. In some embodiments,
first diode device 232 has a forward voltage drop VFB1,second diode device 234 has a forward voltage drop VFB2, and forward voltage drop VFB1 is greater than forward voltage drop VFB2. Also,transistor 210 has a threshold voltage VTH betweengate terminal 212 and S/D terminal 216. In some embodiments, forward voltage drop VFB1 is greater than threshold voltage VTH oftransistor 210. - In some embodiments,
diode device 232 is configured to provide a discharge path betweengate terminal 212 and S/D terminal 216 in order to reduce a voltage difference between voltage VG and voltage VD to be no greater than forward voltage drop VFB1 ofdiode device 232 whendiode device 232 is forward biased and conductive. In some embodiments,diode device 234 is configured to provide a discharge path betweengate terminal 212 and S/D terminal 216 in order to limit a voltage difference between voltage VG and voltage VD to be no greater than forward voltage drop VFB2 ofdiode device 234 whendiode device 234 is forward biased and conductive. In some embodiments,diode devices capacitive devices - In operation,
diode devices capacitor 222 is always in the correct range in order to turn on and offtransistor 210. - In some embodiments,
diode device 232 includes a series of one or more diodes and forward voltage drop VFB1 ofdiode device 232 is the sum of the voltage drops of each diode of the diode series. In some embodiments,diode device 234 includes a series of one or more diodes and forward voltage drop VFB2 ofdiode device 234 is the sum of the voltage drops of each diode of the diode series. - In operation,
capacitive device 222 level-shifts driving signal S3 such that the need to generate control signals having a large voltage swing is avoided. This feature simplifies circuit design and makes it possible to implement a charge pump without the costs associated with a high voltage capability. Detailed operation of various components of pumpingstage circuit 200 is illustrated in conjunction withFIG. 6 . -
FIG. 3 is a circuit schematic diagram of anoutput stage circuit 300 usable incharge pump circuit 100 inFIG. 1 , in accordance with some embodiments. Components inFIG. 3 that are the same or similar to those inFIG. 2 are given the same reference labels, and detailed description thereof is thus omitted. - Compared with pumping
stage circuit 200,output stage circuit 300 does not have control signal terminal CP anddriver 244.Capacitive device 224 is coupled between output terminal and asupply reference terminal 310. In some embodiments,supply reference terminal 310 has a voltage level corresponding to a reference ground voltage level or the zero volt level. In some embodiments,supply reference terminal 310 has a voltage level the same as the logic low level. - In operation,
output stage circuit 300 stores and holds atcapacitive device 224 the charges from a previous pumping stage circuit and outputs a voltage at output terminal OUT having a predetermined pumped voltage level. The capacitance value of thecapacitive device 224 in theoutput stage circuit 300 is set to be sufficiently large to substantially hold the predetermined pumped voltage level while allowing a predetermined current to be drawn by an external circuit. -
FIG. 4 is a circuit schematic diagram of acontrol circuit 400 usable incharge pump circuit 100 inFIG. 1 , in accordance with some embodiments. -
Control circuit 400 includes afeedback voltage terminal 402, areference voltage terminal 404, asupply voltage terminal 408,resistive devices comparator 420, asignal generation circuit 430, and a plurality ofcontrol lines 440. In some embodiments,control circuit 400 includes aclock terminal 406. -
Feedback voltage terminal 402 is coupled withoutput node 104 ofcharge pump circuit 100.Reference voltage terminal 404 is configured to receive a reference voltage having the reference voltage level VREF.Supply voltage terminal 408 is configured to carry a voltage having a supply voltage level. In some embodiments, the supply voltage level is the same as the first logic high level or the second logic high level.Resistive devices supply voltage terminal 408 andfeedback voltage terminal 402.Resistive devices output node 104 to a feedback voltage having a voltage level VFB comparable to the reference voltage level VREF. -
Comparator 420 includes afirst input terminal 422, asecond input terminal 424, and anoutput terminal 426.First input terminal 422 is configured to receive the reference voltage (having the reference voltage level VREF).Second input terminal 424 is configured to receive the feedback voltage (having the feedback voltage level VFB).Comparator 420 compares the values of reference voltage level VREF and feedback voltage level VFB and generates a comparison result atoutput terminal 426. -
Signal generation circuit 430 is coupled with theoutput terminal 426 ofcomparator 420 and, if present,clock terminal 406.Signal generation circuit 430 is also coupled with pumping stage circuits 110[1], 110[2], and 110[N] andoutput stage circuit 120 through the plurality ofcontrol lines 440.Signal generation circuit 430 is configured to receive the comparison result atoutput terminal 426 ofcomparator 420 and a clock signal CLK fromclock terminal 406, and generate control signals SW[1], SW[2], SW[N], SWF, CP[1], CP[2], and CP[N] on the plurality ofcontrol lines 440. In some embodiments,signal generation circuit 430 is further configured to receive a clock signal CLK fromclock terminal 406. -
Control circuit 400 is a non-limiting example. Other types of control circuits usable to generate control signals SW[1], SW[2], SW[N], SWF, CP[1], CP[2], and CP[N] to controlcharge pump circuit 100 based on the pulse width, frequencies, or amplitude information thereof are within the scope of various embodiments of the present disclosure. -
FIG. 8 is a circuit schematic diagram of an examplesignal generation circuit 800 usable as asignal generation circuit 430 in the control circuit inFIG. 4 , in accordance with some embodiments. -
Signal generation circuit 800 includes a D-flip-flop (DFF) 802, an ANDgate 804, and a two-phase,non-overlapping clock generator 808.DFF 802 includes aclock input terminal 806 and acomparator input terminal 826. Two-phase,non-overlapping clock generator 808 includes afirst output terminal 810 and asecond output terminal 812. -
DFF 802 is configured to receive clock signal CLK atclock input terminal 806 and to receive a comparator output, e.g. the comparison result atoutput terminal 426, atlogic input terminal 826.DFF 802 samples the comparator output based on clock signal CLK and outputs a sampled comparator output. - AND
gate 804 is configured to receive the sampled comparator output fromDFF 802 and clock signal CLK, and provide a gated output to two-phase,non-overlapping clock generator 808. In response to a logic high level of the sampled comparator output, ANDgate 804 is configured to output a gated clock signal. In response to a logic low level of the sampled comparator output, ANDgate 804 is configured to output a logic low level. - Two-phase,
non-overlapping clock generator 808 is configured to receive the gated clock signal from ANDgate 804, and in response, create a first pulse signal A atfirst output terminal 810 and a second pulse signal B atsecond output terminal 812. In some embodiments, first pulse signal A and second pulse signal B are used as charge pump control signals SW[i] and CP[i]. In some embodiments,first output terminal 810 andsecond output terminal 812 are coupled with the plurality ofcontrol lines 440. - In some embodiments, first pulse signal A is used as charge pump control signal SW[i] for even values of i and second pulse signal B is used as charge pump control signal SW[i] for odd values of i.
- In some embodiments, first pulse signal A is used as charge pump control signal CP[i] for odd values of i and second pulse signal B is used as charge pump control signal CP[i] for even values of i.
- In operation, signal
generation circuit 800 responds to the comparator output by generating first pulse signal A and second pulse signal B when feedback voltage level VFB is above reference voltage level VREF, and by not generating first pulse signal A and second pulse signal B when feedback voltage level VFB is below reference voltage level VREF. -
Signal generation circuit 800 is a non-limiting example. Other types of signal generation circuits usable to generate control signals SW[1], SW[2], SW[N], SWF, CP[1], CP[2], and CP[N] to controlcharge pump circuit 100, including signal generation circuits without a clock signal input, are within the scope of various embodiments of the present disclosure. -
FIG. 5A is a circuit schematic diagram of anexample diode device 500A usable as adiode device stage circuit 200 inFIG. 2 or inoutput stage circuit 300 inFIG. 3 , in accordance with some embodiments. -
Diode device 500A includes ananode terminal 502, acathode terminal 504, and J diode-connected P-type transistors 510[1] to 510[J] betweenanode terminal 502 andcathode terminal 504. J is a positive integer greater than zero. P-type transistors 510[1] to 510[J] are coupled in series when J is greater than one. To implementdiode device 242 anddiode device 244 using a configuration based ondiode device 500A,diode device 242 is configured to have X (J=X) diode-connected transistors 510[1] to 510[X], anddiode device 244 is configured to have Y (J=Y) diode-connected transistors 510[1] to 510[Y], where X and Y are positive integers. In some embodiments,diode device 242 has a forward voltage drop VFB1 greater than a forward voltage drop VFB2 ofdiode device 244. Therefore, Y is set to be less than X. -
FIG. 5B is a circuit schematic diagram of anotherexample diode device 500B usable as adiode device stage circuit 200 inFIG. 2 or inoutput stage circuit 300 inFIG. 3 , in accordance with some embodiments. Components inFIG. 5B that are the same or similar to those inFIG. 5A are given the same reference labels, and detailed description thereof is thus omitted. -
Diode device 500B includes K diode-connected N-type transistors 520[1] to 520[K] betweenanode terminal 502 andcathode terminal 504. K is a positive integer greater than zero. N-type transistors 520[1] to 520[K] are coupled in series when K is greater than one. To implementdiode device 232 anddiode device 234 using a configuration based ondiode device 500B,diode device 232 is configured to have X (K=X) diode-connected transistors 520[1] to 520[X], anddiode device 234 is configured to have Y (K=Y) diode-connected transistors 520[1] to 520[Y], where X and Y are positive integers. In some embodiments,diode device 232 has a forward voltage drop VFB1 greater than a forward voltage drop VFB2 ofdiode device 234. Therefore, Y is set to be less than X. - In some embodiments, one of
diode device 232 ordiode device 234 is implemented based on the configuration ofdiode device 500A, and the other one ofdiode device 232 ordiode device 234 is implemented based on the configuration ofdiode device 500B. In some embodiments,diode device 232 ordiode device 234 is implemented by other types of diode devices different fromdiode device 500A anddiode device 500B. -
FIG. 6 is a timing diagram of voltage levels at various nodes ofcharge pump circuit 100 inFIG. 1 , which is further illustrated in conjunction withFIGS. 2-4 , in accordance with some embodiments. - In the example depicted in
FIG. 6 , the number of pumping stage circuits (i.e., the number N inFIG. 1 ) is set to be two, and charge pump circuit is configured to be a negative pump. The voltage level VIN is set to be 0 V, and the voltage level VOUT is set to be −2.2 V. The charge pump circuit as illustrated in conjunction withFIGS. 1-4 is also usable as a positive pump. Different configurations and settings of thecharge pump circuit 100 are within various embodiments of the present disclosure. -
Waveform 602 corresponds to the voltage level of signal S1 of first pumping stage circuit 110[1].Waveform 604 corresponds to the voltage level of signal S2 of first pumping stage circuit 110[1].Waveform 612 corresponds to the voltage level of voltage VD of first pumping stage circuit 110[1].Waveform 614 corresponds to the voltage level of voltage VG of first pumping stage circuit 110[1].Waveform 622 corresponds to the voltage level of voltage VD of second pumping stage circuit 110[2].Waveform 632 corresponds to the voltage level of voltage VD ofoutput stage circuit 120. - The following illustration, if not otherwise specified, is primarily based on the operation of first pumping stage circuit 110[1] using the reference labels from pumping
stage circuit 200 inFIG. 2 . The operations oftransistors 210 andcapacitive device 222 of second pumping stage circuit 110[2] andoutput stage circuit 120 are similar to the operations oftransistor 210 andcapacitive device 222 of first pumping stage circuit 110[1]. The operation ofcapacitive device 224 of second pumping stage circuit 110[2] is similar to the operation ofcapacitive device 224 of first pumping stage circuit 110[1]. Detailed description thereof is thus omitted. - In this embodiment, each signal of signals S1, S2, S3, and S4 has a logic high level of 1.8 volts (V) and a logic low level of 0.0 V. In some embodiments, each signal of signals S1 and S3 has a logic high level different from that of signal S2 and S4. In some embodiments, each signal of signals S1 and S3 has a logic high level of 2.5 V, and each signal of signals S2 and S4 has a logic high level of 1.8 V.
- Prior to time T1 during a steady state operation of
charge pump circuit 100, signal S1 (waveform 602) and signal S2 (waveform 604) of first pumping stage circuit 110[1] are at the low logic level. Signal S3 (not shown) and signal S4 (not shown) of first pumping stage circuit 110[1] are thus at the signal high level. Voltage VD of first pumping stage circuit 110[1] is at an input voltage level from a power source or a previous pumping stage circuit, such as 0.0 volt for first pumping stage circuit 110[1] in this example. Also, voltage VG of first pumping stage circuit 110[1] is at a voltage level that equals the input voltage level plus the forward voltage drop VFB1 ofdiode device 232, such as VFB1 in this example. Because forward voltage drop VFB1 is set to be greater than threshold voltage VTH oftransistor 210,transistor 210 is turned on to pass the input voltage level (e.g., 0.0 V in this example) to voltage VD. - At time T1, signal S1 (waveform 602) transitions from the low logic level to the high logic level. Signal S2 (waveform 604) remains at the low logic level. Signal S3 (not shown) thus transitions from the high logic level to the low logic level while signal S4 (not shown) remains at the signal high level. Through the operation of
capacitive device 222 of first pumping stage circuit 110[1], at time T1, voltage VG (waveform 614) of first pumping stage circuit 110[1] is pushed down by about 1.8 V. Meanwhile,diode device 234 of first pumping stage circuit 110[1] is also providing a discharge path to pull voltage VG (waveform 614) and voltage VD (waveform 612) toward each other. As a result of these contradictory pulling forces, at time T1, voltage VG (waveform 614) transitions from voltage level VFB1 to a voltage level that is a few hundred millivolts (mV) higher than a voltage level of voltage level VFB1 minus 1.8 V. The voltage differences between the gate terminal oftransistor 210 and S/D terminals oftransistor 210 are insufficient to turn ontransistor 210. Voltage VD (waveform 614) remains at 0.0V. Transistor 210 is thus turned off. - After time T1 but before time T2, voltage VG (waveform 614) and voltage VD (waveform 612) are pulled toward each other through
diode device 234.Transistor 210 remains turned off. In some embodiments, the time period between time T1 and time T2 is set to be insufficient to pull voltage VG to be sufficiently large to turn ontransistor 210 at time T2. In some embodiments, the time period between time T1 and time T2 is sufficiently small that the voltage change of voltage VG (waveform 614) or the voltage change of voltage VD (waveform 612) is less than 100 mV. - At time T2, signal S2 (waveform 604) transitions from the low logic level to the high logic level. Signal S1 (waveform 602) remains at the high logic level. Signal S4 (not shown) thus transitions from the high logic level to the low logic level while signal S3 (not shown) remains at the signal low level. Through the operation of
capacitive device 224, at time T2, voltage VD (waveform 612) is being pushed down by about 1.8 V. Meanwhile, through the charge sharing betweencapacitive device 224 and another capacitive device of the next pumping stage circuit (e.g.,capacitive device 224 of second pumping stage circuit 110[2]) or a corresponding output stage circuit 120 (e.g.,capacitive device 224 of output stage circuit 120), voltage VD is also being pulled toward a steady state output voltage level of this pumping stage, such as −1.1 V in this example. In some embodiments, the charge sharing is also controlled by adjusting the frequencies of control signals SW[1], SW[2], SW[N], SWF, CP[1], CP[2], and CP[N] and/or by adjusting the voltage level of signal S4. Voltage VG (waveform 314) is pulled down slightly at time T2 whendiode device 234 goes from conductive to reverse-biased. As a result, at time T2, voltage VD (waveform 612) transitions from 0.0 V to a voltage level that is a few hundred mV higher than a voltage level of −1.8V. Transistor 210 remains turned off. - After time T2 but before time T3, voltage VG (waveform 614) remains at about the same voltage level after
diode devices transistor 210.Transistor 210 remains turned off. - At time T3, signal S2 (waveform 604) transitions from the high logic level to the low logic level. Signal S1 (waveform 602) remains at the high logic level. Signal S4 (not shown) thus transitions from the low logic level to the high logic level while signal S3 (not shown) remains at the signal low level. Through the operation of
capacitive device 224, at time T3, voltage VD (waveform 612) is being pulled up by about 1.8 V. Meanwhile,diode device 234 is also providing a discharge path to pull voltage VG (waveform 614) and voltage VD (waveform 612) toward each other. As a result, at time T3, voltage VD (waveform 612) transitions from the steady state output voltage level (e.g., −1.1 V in this example) to a voltage level that is a few hundred mV lower than a voltage level of 0.7 V (i.e, −1.1 V plus 1.8 V). The voltage differences between the gate terminal oftransistor 210 and S/D terminals oftransistor 210 are insufficient to turn ontransistor 210.Transistor 210 remains turned off. - After time T3 but before time T4, voltage VG (waveform 614) and voltage VD (waveform 612) are pulled toward each other through
diode device 234.Transistor 210 remains turned off. In some embodiments, the time period between time T3 and time T4 is sufficiently small that the voltage change of voltage VG (waveform 314) or the voltage change of voltage VD (waveform 612) is less than 100 mV. - At time T4, signal S1 (waveform 602) transitions from the high logic level to the low logic level. Signal S2 (waveform 604) remains at the low logic level. Signal S3 (not shown) thus transitions from the low logic level to the high logic level while signal S4 (not shown) remains at the signal high level. Through the operation of
capacitive device 222, at time T4, voltage VG (waveform 614) is being pulled up by about 1.8 V. Meanwhile,diode device 232 is also providing a discharge path to pull voltage VG (waveform 614) toward voltage VD. As a result, at time T4, voltage VG (waveform 614) transitions to a voltage level that is a few hundred mV higher than voltage level VFB1. The voltage difference between the gate terminal oftransistor 210 and S/D terminal 216 is sufficient to turn ontransistor 210. - After time T4 but before time T5, voltage VD (waveform 612) is pulled toward and then remains at the steady state input voltage level (e.g., 0 V in this example), and voltage VG (waveform 614) is pulled toward and then remains at about forward voltage drop VFB1 of
diode device 232 plus the steady state input voltage level.Transistor 210 remains turned on. - At time T5, the next operation cycle of pumping
stage circuit 200 begins. Time T5 corresponds to time T1 of the next operation cycle. - Second pumping stage circuit 110[2] is operated in a manner similar to first pumping stage circuit 110[1], except the corresponding control signals thereof are non-overlapping signals to the counterpart signals of first pumping stage circuit 110[1]. As a result, voltage VD of pumping stage circuit 110[2] (waveform 622) is at −1.1V during time T1 to time T4 and is pumped to −2.2 V during time T4 to time T5. Transistor 210 of
output stage circuit 120 is operated in a manner similar totransistor 210 of first input stage 110[1].Capacitive device 224 ofoutput stage circuit 120 is configured to hold the voltage level of voltage VD at −2.2 V whentransistor 210 ofoutput stage circuit 120 is turned off during time T1 to time T4. Capacitive device 224 ofoutput stage circuit 120 is also configured to receive the charges from thecapacitive device 224 of second pumping stage circuit 110[2] whentransistor 210 ofoutput stage circuit 120 is turned on during time T4 to time T5. As a result, voltage VD ofoutput stage circuit 120 remains at −2.2 V. - As depicted in
FIG. 6 andFIG. 2 , through the discharge path provided bydiode device 232 and the DC separation betweengate terminal 212 oftransistor 210 and the output terminal of driver 242 (i.e., signal S3), the voltage difference betweengate terminal 212 and S/D terminal 216 and the voltage difference betweengate terminal 212 and S/D terminal 214 whentransistor 210 is turned on is kept at about forward voltage drop VFB1 ofdiode device 232. In some embodiments, forward voltage drop VFB1 ofdiode device 232 is set to be less than the logic high level, such as 1.8 V in this example. For a pump stage circuit at a later stage of thecharge pump circuit 100 or theoutput stage circuit 120, regardless the corresponding input voltage level or the pumped voltage level, a transistor corresponding totransistor 210 thus has a gate terminal to S/D terminal voltage adjusted by forward voltage drop VFB1 ofdiode device 232, which is less than the logic high level when thetransistor 210 is turned on. -
FIG. 7 is a flow chart of amethod 700 of operating a pumping stage circuit inFIG. 2 , in accordance with some embodiments.FIG. 7 is illustrated in conjunction with the example depicted inFIG. 2 . It is understood that additional operations may be performed before, during, and/or after themethod 700 depicted inFIG. 7 , and that some other processes may only be briefly described herein. -
Method 700 begins withoperation 710, where a voltage level at a first end of a capacitive device, such as signal S3 betweendriver 242 andcapacitive device 222, is caused to transition from a first voltage level to a second voltage level responsive to a first logic value of a control signal. In some embodiments, the first voltage level corresponds to a logic low level, the second voltage level corresponds to a logic high level, the control signal corresponds to signal S1, and the first logic value corresponds to a logic low value. -
Method 700 proceeds tooperation 720, where a voltage level at a second end ofcapacitive device 222, such as voltage VG, is caused to transition to a third voltage level responsive to the second voltage level at the first end of the capacitive device. The second end ofcapacitive device 222 is electrically coupled with agate terminal 212 of atransistor 210. - In some embodiments,
operations FIG. 6 . -
Method 700 proceeds tooperation 730, where a first voltage difference betweengate terminal 212 and a source/drain (S/D)terminal 216 oftransistor 210 is adjusted by a first diode device, such asdiode device 232, whentransistor 210 is turned on andfirst diode device 232 is forward biased and conductive.First diode device 232 has an anode coupled withgate terminal 212 oftransistor 210 and a cathode coupled with S/D terminal 216 oftransistor 210. In some embodiments,operation 730 corresponds to the signal transitions from time T4 to time T5 in the timing diagram inFIG. 6 . -
Method 700 proceeds tooperation 740, where a voltage level (e.g., signal S3) at the first end ofcapacitive device 222 is caused to transition from the second voltage level to the first voltage level responsive to a second logic value of a control signal. In some embodiments, the second logic value corresponds to a logic high value. As a result, voltage VG is caused to transition to a fourth voltage level that is insufficient to turn ontransistor 210. In some embodiments,operation 740 corresponds to the signal transitions at time T1 in the timing diagram inFIG. 6 . -
Method 700 proceeds tooperation 750, where a second voltage difference between S/D terminal 216 of thetransistor 210 andgate terminal 212 of transistor 201 is adjusted by a second diode device, such asdiode device 234, when thetransistor 210 is turned on and thesecond diode device 234 is forward biased and conductive.Second diode device 234 has an anode coupled with the S/D terminal 216 of thetransistor 210 and a cathode coupled with thegate terminal 212 of thetransistor 210. In some embodiments,operation 750 corresponds to the signal transitions from time T1 to time T2 and/or from time T3 to time T4 in the timing diagram inFIG. 6 . - In some embodiments,
first diode device 232 has a forward voltage drop VFB1,second diode device 234 has a forward voltage drop VFB2, and forward voltage drop VFB1 is greater than forward voltage drop VFB2. Also,transistor 210 has a threshold voltage VTH betweengate terminal 212 and S/D terminal 216. In some embodiments, forward voltage drop VFB1 is greater than threshold voltage VTH oftransistor 210. - In some embodiments, operations 710-750 are applicable to a method of operating an
output stage circuit 300 inFIG. 3 . -
Method 700 proceeds tooperation 760, where a voltage level at S/D terminal 216 oftransistor 210 is pumped to a predetermined pumped voltage level in response to another control signal, such as control signal S2. In some embodiments,operation 760 corresponds to the signal transitions from time T2 to time T3 in the timing diagram inFIG. 6 . - In accordance with one embodiment, a charge pump circuit includes a sub-circuit, which is a pumping stage circuit or an output stage circuit. The sub-circuit includes an input terminal, an output terminal, a transistor, a first capacitive device, a first diode device, and a second diode device. The transistor has a first source/drain (S/D) terminal coupled with the input terminal, a second S/D terminal coupled with the output terminal, and a gate terminal. The first capacitive device has a first end coupled with the gate terminal of the transistor and a second end configured to receive a first driving signal. The first diode device has a cathode coupled with the second S/D terminal of the transistor and an anode coupled with the gate terminal of the transistor. The second diode device has a cathode coupled with the gate terminal of the transistor and an anode coupled with the second S/D terminal of the transistor.
- In accordance with another embodiment, a charge pump circuit includes an input node, an output node, N pumping stage circuits, and an output stage circuit. N is a positive integer greater than zero. Each pumping stage circuit of the N pumping stage circuits includes an input terminal and an output terminal. The output stage circuit includes an input terminal and an output terminal. The input terminal of a first pumping stage circuit of the N pumping stage circuits is coupled with the input node. The output terminal of a n-th pumping stage circuit of the N pumping stage circuits is coupled with the input terminal of a (n+1)-th pumping stage circuit of the N pumping stage circuits, where n is a positive integer and 1≦n≦(N−1). The output terminal of the N-th pumping stage circuit of the N pumping stage circuits is coupled with the input terminal of the output stage circuit. The output terminal of the output stage circuit is coupled with the output node. One of the N pumping stage circuits further includes a transistor, a first capacitive device, a second capacitive device, a first diode device, and a second diode device. The transistor has a first source/drain (S/D) terminal coupled with the input node of the one of the N pumping stage circuits, a second S/D terminal coupled with the output node of the one of the N pumping stage circuits, and a gate terminal. The first capacitive device has a first end coupled with the gate terminal of the transistor and a second end configured to receive a first driving signal. The second capacitive device has a first end coupled with the output node of the one of the N pumping stage circuits and a second end configured to receive a second driving signal. The first diode device has a cathode coupled with the second S/D terminal of the transistor and an anode coupled with the gate terminal of the transistor. The second diode device has a cathode coupled with the gate terminal of the transistor and an anode coupled with the second S/D terminal of the transistor.
- In accordance with another embodiment, a method of operating a pumping stage circuit or an output stage circuit of a charge pump circuit is disclosed. The method includes causing a voltage level at a first end of a capacitive device to transition from a first voltage level to a second voltage level responsive to a first logic value of a control signal. The method also includes causing a voltage level at a second end of the capacitive device to transition to a third voltage level responsive to the second voltage level at the first end of the capacitive device, the second end of the capacitive device being electrically coupled with a gate terminal of a transistor; and adjusting a first voltage difference between the gate terminal and a source/drain (S/D) terminal of the transistor by a first diode device when the transistor is turned on and the first diode device is forward biased and conductive. The first diode device has an anode coupled with the gate terminal of the transistor and a cathode coupled with the S/D terminal of the transistor.
- The foregoing outlines features of several embodiments so that those skilled in the art may better understand the aspects of the present disclosure. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions, and alterations herein without departing from the spirit and scope of the present disclosure.
Claims (20)
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US14/956,061 US11611276B2 (en) | 2014-12-04 | 2015-12-01 | Charge pump circuit |
TW104140470A TWI620405B (en) | 2014-12-04 | 2015-12-03 | Charge pump circuit and method of operating a pumping stage circuit or an output stage circuit of a charge pump circuit |
DE102015121020.7A DE102015121020A1 (en) | 2014-12-04 | 2015-12-03 | Charge pump circuit |
KR1020150172447A KR101867656B1 (en) | 2014-12-04 | 2015-12-04 | Charge pump circuit |
CN201610072649.3A CN106817021B (en) | 2015-12-01 | 2016-02-02 | Charge pump circuit |
US18/185,059 US20230223846A1 (en) | 2014-12-04 | 2023-03-16 | Charge pump circuit and method |
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US8390365B2 (en) * | 2010-10-18 | 2013-03-05 | National Tsing Hua University | Charge pump system for low-supply voltage |
US8981836B2 (en) * | 2010-11-30 | 2015-03-17 | Infineon Technologies Ag | Charge pumps with improved latchup characteristics |
US20130321069A1 (en) * | 2011-01-14 | 2013-12-05 | Panasonic Coporation | Charge pump circuit |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
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CN112684928A (en) * | 2019-10-17 | 2021-04-20 | 奇景光电股份有限公司 | Charge pump circuit suitable for touch display integrated driver |
CN113872435A (en) * | 2021-10-19 | 2021-12-31 | 普冉半导体(上海)股份有限公司 | Single-stage circuit of positive and negative voltage charge pump and four-phase charge pump circuit |
Also Published As
Publication number | Publication date |
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KR101867656B1 (en) | 2018-06-18 |
US11611276B2 (en) | 2023-03-21 |
KR20160067804A (en) | 2016-06-14 |
TWI620405B (en) | 2018-04-01 |
TW201631876A (en) | 2016-09-01 |
DE102015121020A1 (en) | 2016-06-09 |
US20230223846A1 (en) | 2023-07-13 |
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